Sensors are often employed in applications where it is desirable to track displacement of a physical object. For example, sensors may be used to track the movement of a component of a machine (e.g., for robotics applications) or of a person's hand or some other body part (e.g., for video game or biomechanical applications).
In some aspects the technology employed in a given sensor depends on the requirements of the corresponding application. Relatively low performance applications commonly employ low cost sensors that are based on Piezo-resistor technology or some other similar technology. For example, a relatively low cost Piezo-resistor-based sensor may be used to coarsely sense movements having a bandwidth on the order of 100 Hz.
In general, such low cost sensors may not be employed in higher performance applications because the inherent characteristics of these sensors may tend to limit their usefulness in such applications. For example, a Piezo sensor may have a low frequency pole-zero doublet that results in slow settling components as well as a device memory and/or device decay effect that increases with use over time. Also, a Piezo sensor may be relatively sensitive to changes in temperature. These characteristics may, in turn, adversely affect the accuracy, resolution, and reliability of sensed measurements. In some cases, feedback techniques may be used to compensate for the doublet in an attempt to improve the bandwidth of the sensor. However, these techniques may involve a difficult pole-zero cancellation operation.
Higher performance applications may employ more accurate, more robust, or higher bandwidth sensors such as Hall effect or optical sensors. However, in general, these types of sensors are more complex and more expensive than lower performance sensors.
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